Christopher Booker's hefty tome of cultural archaeology is peculiar, repetitive, near-barmy and occasionally rather good. He takes the commonplace idea that there are only so many stories in the world and follows it very far indeed. Obsession is almost too small a word to describe an enterprise which has consumed 34 years and required a reading list more or less synonymous with the history of literature.

The book's construction is deceptive. For more than 200 pages, Booker deals with plots solely in terms of their shapes, with no value judgments apparent. He extracts a single, five-part template from, for instance, the Icarus myth, the legend of Faust, Macbeth, Dr Jekyll and Mr Hyde and Lolita. He throws the bones of a thousand stories into the pot and renders them down. He adds films along with a few operas and television series.

It's obvious there is more to a novel than its plot, but the point is even clearer when applied to cinema. A film's plot is only one aspect of its screenplay. Plenty of other elements can claim to change, and even determine, overall meaning: dialogue, acting, design, camerawork, editing and music, to name only six. Of these things, and their equivalents in prose, Booker has nothing to say.

In any case, his grip is slacker on film than on books. His mistakes in literature are largely motivated by dislike, as when he asserts that William Burroughs, 'after writing a pornographic novel, The Naked Lunch, went on to experiment with stories in which the sentences were designed to be randomly jumbled up and read in any sequence'. That's a wholly inaccurate description of the cut-up method, which was also used in Naked Lunch. His film mistakes have more to do with carelessness, misrepresenting the ending of Jaws, or saying Star Wars was set in 'the distant future' of our galaxy'. The clue here is in the giant opening titles: 'Long, long ago, in a galaxy far, far away...'

After he has established his basic plots (Overcoming the Monster, Rags to Riches, The Quest, Voyage and Return, Comedy, Tragedy and Rebirth), Booker peels off the anorak to reveal... well, not quite a cassock, but a robe suitable to an interpreter of 'the cosmic mind'.

Having turned the world's plots into a narrative sludge, he filters the results. There turn out to be two master-narratives, one inspirational and one cautionary - comedy and tragedy. In comedy, proportion is restored and the ego overcome; in tragedy, distortion becomes so severe that the ego that suffers it must be destroyed for the renewal of the wider order. Proper stories end in marriage or death. Booker's inspiration throughout is Jung: the hero of classic fairy stories must rescue or win the princess who represents his anima, the feminine principle which he must incorporate if he is to become whole.

As Booker sees it, story-telling began to change about 200 years ago. Starting with the Romantic movement, the ego split from the self: the resulting works couldn't avoid taking archetypal shapes, but failed to deliver the required resolutions. Wholeness was lost, though the surviving structures of narrative testified to a continuing need for it.

Idealism - the sense of how life should be - is a part of the urge to tell stories and make art, but it can't be the whole of the endeavour. Even in stories that perform the task Booker prescribes, there are jarring details: when Odysseus returns to Ithaca, he not only kills his wife's suitors but orders the execution of a dozen serving-women who had consorted with them. His son, Telemachus, who has been sharing the palace with them, hangs them in a row from a ship's rope. There's a vivid image of the women as trapped birds. Their death is made cruel and dishonourable on principle.

This residue of sadism at the moment when the narrative is reconstituting wholeness doesn't diminish The Odyssey as a work of art, but it certainly raises doubts about the healing balm of the happy ending.

In general, writers are penalised by Booker for including too much of the world around them. Art, by this account, has no function of witness. Experience is not its true domain. The archetypes are deeper than history, though history can sometimes restrict or enhance access to them. With the Second World War, men were freed to play fully masculine roles, while 'women could again become feminine, courageously representing those values of heart and soul for which so much was now being risked'. This caricature insults the women who joined the workforce in such great numbers.

Booker's best chapter is on Oedipus Rex and Hamlet, masterpieces that contrive to be exceptions to some of his rules as well as archetypes in their own right. These plays force him to engage with things other than plot, although when he tries to get his readers to ignore the distracting personality of Hamlet in favour of deeper patterns, he seems almost to be saying: 'Don't listen to Shakespeare; listen to me.'

He sets up criteria for art, and ends up condemning Rigoletto, The Cherry Orchard, Wagner, Proust, Joyce, Kafka and Lawrence - the list goes on - while praising Crocodile Dundee, E.T. and Terminator 2 ('The archetype has again reformed itself into the image of wholeness which lies at the heart of what our urge to imagine stories is about'). Star Wars fails because it doesn't liberate the anima, while in the original Terminator the princess has to free herself, which won't do.

Faced with that scorecard, most of us would change criteria. Booker fights on, struggling with the paradoxes of his position. These are hydra heads, richly propagated by the knife that cuts them.

If plot is the genetic code of a work of art, how can different productions of a play or remakes of a film be any different? Why see more than one comedy that satisfies the archetype? Why write more than one?

Booker sees his narrative archetypes as underlying politics, both hard (communism, fascism) and soft (feminism, environmentalism). He never manages, though, to explain what stories offer to female readers. The proper function of female characters, after all, is to represent qualities which the hero can in due course absorb within himself. The whole process of self-integration has its grotesque side, since the hero, having matured by seeing beyond his own ego, is rewarded with the revelation that all the other people in the story were aspects of himself all along.

If the ideal of an integrated personality was just that - an ideal - it would be harmless. But it seems to be an attainable goal: 'In anyone who has achieved personal maturity, we see how this combines strength of character and the capacity for ordered thinking with selfless feeling and the intuitive ability to see objectively and whole.' There are no pronouns on show here, but how could this mature person be female, when female qualities are supposed to irradiate masculine ones rather than stand alone?

Homosexuals don't need to be specifically excluded, since their desire reveals their failure. Never mind that EM Forster and Virginia Woolf tried harder than any in their time to keep faith with wholeness of personality. Their names don't feature in The Seven Basic Plots, though it would be reassuring to know that Booker had at least read their work, rather than discounting it in advance on ideological grounds. One distortion among thousands, in a stimulating, ambitious and unsatisfying book - and all in the name of seeing whole.